Want to make a mud house? Clay's journey from artist to builder.

Delftware vase made in London in the Chinese style. You can see the red earthenware clay peeking through the chipped glaze at the bottom.

In last week's post, I said that "Delftware potters referred to the work as porcelain: however, it was a cheap version of the Chinese pottery of the time." That got me thinking about why they were copying instead of using the real thing. Which led me to the history of kaolin, or China clay. The name kaolin is derived from Gaoling –Chinese: Gāolǐng; meaning 'High Ridge'. The name entered English in 1727 from the French version of the word: kaolin, following a Frenchmen's report on making Chinese porcelain. This prompted others to look for it.

When delftware was made (the 1600s), China was the only country to discover kaolin and realize its benefits. Let me remind you here that clay is mined from the ground; what a potter uses is called a clay body. Porcelain's body is composed of the raw materials of kaolin, feldspar, quartz, and ball clay (another light color clay known for its plasticity). Together they create three unique technical characteristics: hardness, whiteness, and translucency. In other words, it's non-porous, durable, and beautiful, making it perfect for dinnerware and tile. That's how kaolin is important to ceramics.

A kaolin mine in Georgia.

Click the map to see North Carolina mines and their locations.

It's important to us too. We interact with kaolin daily. It is used in toothpaste, cosmetics, incandescent light bulbs, organic farming, whitewash, to soothe a stomach as in Kaopectate, to induce blood clotting, and as beauty wraps and masks for the skin. Because of its hardness and high refractory qualities, the space industry also makes parts using porcelain.

Kaolin is essential to our economy, with the United States being it's top exporter. Belgium, the United Kingdom, Brazil, Ukraine, China, and six other countries mine it too.

Clay will be a part of our future. As climate change increases, how we build will have to change. Some architects know the role clay has played in creating a comfortable and sustainable life thru the ages and have left high-tech building methods behind. Mud-walled houses have many ecological advantages, the most significant being that clay walls have a high thermal mass, absorbing and storing heat slowly, making the home less likely to overheat. I doubt they would get a certificate of occupancy here in the states but let me leave you with some pie-in-the-sky clay houses and a promise to look into it further.

These images are of sustainable houses built in the village of Bania, Bulgaria.